A conventional electronic circuit apparatus such as a communicating apparatus in a vehicular electronic key system has a casing to contain a battery and a circuit board on which electronic components are mounted (Patent Document 1).
Patent Document 1: JP-2004-52471 A
A main body of the casing is formed of a flat card-shaped box having a bottom to include a circuit-board containing portion and battery containing portion, which contain the circuit board and battery, respectively. The circuit board and battery are hermetically enclosed in the main body of the casing using a covering sheet, i.e., a lid. Each terminal, an end portion of which is soldered on the circuit board, is extended into the battery container to be pressed to contact the battery; therefore, each terminal is previously deformed to bend towards a battery position where the battery is to be inserted.
In the conventional electronic circuit apparatus, both the front and rear surfaces of the circuit board are enclosed within the casing, increasing the thickness of the casing or the apparatus to possibly worsening portability.
To decrease the thickness of the apparatus, the following method can be adopted: one surface of a circuit board, on which an electronic component is mounted, is sealed with resin to form a casing; the other surface of the circuit board having no electronic component mounted is used as an outer surface of the casing. Here, when the casing is molded with resin, a mold for forming a battery containing space is required.
However, since the above terminal needs to be previously deformed to bent towards the battery position, the mold for forming the battery containing space cannot be a slide type mold, which will be prevented from moving by the bent terminal. Consequently, the mold becomes complicated.
Each terminal needs to be soldered on the circuit board at its end portion and to contact the battery at the other end portion; therefore, the terminal is considerably extended from the circuit board where the end portion is soldered. This makes it difficult for the circuit board to securely support the terminal. Consequently, the terminal is soldered on the circuit board by hand, instead of being automatically mounted. The number of production processes for producing the electronic circuit apparatus increases, posing a problem.